DBpedia Snapshot (Virtuoso PAGO) EBS-backed EC2 AMI

Introduction

In addition to the Instance-backed EC2 AMI that has been available since 2008, a standard unpopulated Virtuoso instance is available as an EBS-backed EC2 AMI based on either a BYOL (Bring Your Own License) or a PAGO (Pay As You Go) basis. In each case, the AMI delivers a preconfigured Virtuoso instance.

We also now offer two PAGO variants, both pre-loaded with DBpedia data.

This type of AMI provides several fundamental benefits including —

Prerequisites

Instantiating DBpedia Snapshot (Virtuoso PAGO) via Web Interface

  1. Locate the DBpedia Snapshot (Virtuoso PAGO) image in AWS Marketplace and click the Continue button.

    AWS Marketplace DBpedia Snapshot (Virtuoso PAGO)

  2. Choose a suitable size EC2 Instance Type and Key Pair, then click on the button Launch with 1-click button.

    AWS Marketplace DBpedia Snapshot (Virtuoso PAGO) Launch on EC2

  3. A confirmation dialog will be presented indicating the image has been deployed.

    AWS Marketplace DBpedia Snapshot (Virtuoso PAGO) now Deployed

  4. Check the in the AWS Console EC2 images Web Interface that the image has been successfully instantiated.

    AWS EC2 Launched Image

  5. Load the Virtuoso Admin Console (a/k/a Conductor) in your browser to confirm all is running properly: 

    http://{amazon-ec2-ami-dns-name-or-ip-address}:8890/conductor

First-time Setup & Usage Notes

These steps in this section are only necessary the first time you start the Virtuoso instances on the AMI. This section may be ignored thereafter, as it is not necessary after AMI reboots.

There are two Virtuoso instances in this AMI. One which comes up quickly, with no significant content, so you know the AMI is basically functional; and one which comes up more slowly, with the full DBpedia dataset, which takes significant time to start due to some Amazon requirements for such AWS instances.

Basic Instance

  1. ssh into your instantiated AMI using a command of the form — 

    ssh -i {secure-pem-file} ec2-user@{amazon-ec2-dns-name-or-ip-address}

  2. The Virtuoso DBMS Server for the Basic Instance will have started with the AMI. You can verify this with -- 

    ps -ef | grep "virt*" | grep -v grep

    • If you do not see a running instance, execute the following commands, and then repeat the command above. 

      cd /opt/virtuoso
. ./virtuoso-environment.sh    # this must start dot-space-dot-slash
virtuoso-start.sh database

  3. We strongly recommend you now use the Conductor to change the password for the 'dba' user from the the AMI instance-id.

    1. Retrieve the AMI instance-id by either --
      • checking the AMI properties presented by the Amazon AWS console UI --

        AWS Console

      • executing the following command in the Linux shell -- 

        curl http://169.254.169.254/latest/meta-data/instance-id

    2. Execute this command sequence -- 

      cd /opt/virtuoso
. ./virtuoso-environment.sh    # this must start dot-space-dot-slash
cd bin
./isql localhost:1112 dba

    3. When prompted for password, provide the instance-id
    4. At the SQL> prompt, execute these two commands -- 

      vad_install('/opt/virtuoso/vad/conductor_dav.vad',0)
quit

    5. Load the Conductor interface. 

      http://{amazon-ec2-ami-dns-name-or-ip-address}:8890/conductor

      • If you get any error at this point, execute the following commands, and then re-try loading the Conductor in your web browser. 

        cd /opt/virtuoso
. ./virtuoso-environment.sh    # this must start dot-space-dot-slash
virtuoso-stop.sh database
virtuoso-start.sh database

    6. At the authentication challenge, log in as the dba user, with the AMI instance-id as the password. Note: If unable to connect to the Virtuoso server using the instance-id as password, please register with our Support Site, and create a Support Case for fastest assistance.
    7. Drill down to System Admin → User Accounts.
    8. Locate the dba user, and click the associated Edit link.
    9. The form allows many things to be changed. For now, just input your desired password into both Password and Confirm Password boxes, and click the Save button.
    10. You can now perform other administrative tasks through the Conductor interface, or return to basic use.

DBpedia Instance

  1. ssh into your instantiated AMI using — 

    ssh -i {secure-pem-file} ec2-user@{ec2-dns-name-or-ip-address}

  2. Stop the Basic Instance (to conserve system and license resources) by running — 

    virtuoso-stop.sh dbpedia

  3. Start the Virtuoso DBMS Server against the DBpedia Database by issuing the commands below. Note: At initial launch, it takes the Virtuoso DBMS Server approximately 20 minutes to bring the DBpedia database online, due to its size. 

    cd /opt/virtuoso
. ./virtuoso-environment.sh    # this must start dot-space-dot-slash
virtuoso-start.sh dbpedia

  4. We strongly recommend you now use the Conductor to change the password for the 'dba' user from the the AMI instance-id.

    1. Retrieve the AMI instance-id by either --
      • checking the AMI properties presented by the Amazon AWS console UI --

        AWS Console

      • executing the following command in the Linux shell -- 

        curl http://169.254.169.254/latest/meta-data/instance-id

    2. Load the Conductor interface 

      http://{amazon-ec2-ami-dns-name-or-ip-address}/conductor

      • If you get any error at this point, execute the following commands, and then re-try loading the Conductor in your web browser. 

        cd /opt/virtuoso
. ./virtuoso-environment.sh    # this must start dot-space-dot-slash
virtuoso-stop.sh dbpedia
virtuoso-start.sh dbpedia

    3. At the authentication challenge, log in as the dba user, with the AMI instance-id as the password. Note: If unable to connect to the Virtuoso server using the instance-id as password, please register with our Support Site, and create a Support Case for fastest assistance.
    4. Drill down to System Admin → User Accounts.
    5. Locate the dba user, and click the associated Edit link.
    6. The form allows many things to be changed. For now, just input your desired password into both Password and Confirm Password boxes, and click the Save button.
    7. You can now perform other administrative tasks through the Conductor interface, or return to basic DBpedia use.

DBpedia Snapshot (Virtuoso PAGO) Database Interaction via Web Interface

Once online, your DBpedia Snapshot instance will be ready for use from —

Administering the Virtuoso Instance via SSH

All scripts for starting and stopping the Virtuoso instance are found in the following locations —

License Manager

The OpenLink License Manager must be launched before you launch the Virtuoso instance, and must remain running at all times for Virtuoso to run.

Virtuoso Server

Virtuoso DBpedia Server

Command-line Interaction with the Virtuoso Database Instance

  1. Set the Virtuoso environment variables by running the command below. Note: This does and must start with dot-space-slash. 

    . /opt/virtuoso/virtuoso-enterprise.sh

  2. Run the Virtuoso "isql" command line tool to connect to the database. Note: your EC2 AMI's instance-id will be the dba user's password, until you change it (as recommended above). 

    $ isql 1111 -U dba -P {Password}
Connected to OpenLink Virtuoso
Driver: 07.10.3214 OpenLink Virtuoso ODBC Driver
OpenLink Interactive SQL (Virtuoso), version 0.9849b.
Type HELP; for help and EXIT; to exit.
SQL>

  3. Run the "tables" command to obtain a list of tables in the default schema 

    SQL> tables;
Showing SQLTables of tables like 'NULL.NULL.NULL', tabletype/colname like 'NULL'
TABLE_QUALIFIER  TABLE_OWNER      TABLE_NAME       TABLE_TYPE       REMARKS
VARCHAR          VARCHAR          VARCHAR          VARCHAR          VARCHAR
_______________________________________________________________________________

DB               DBA              ADMIN_SESSION    SYSTEM TABLE     NULL
DB               DBA              ADM_OPT_ARRAY_TO_RS_PVIEW  SYSTEM TABLE     NULL
DB               DBA              ADM_XML_VIEWS    SYSTEM TABLE     NULL
.
.
.
DB               DBA              SYS_SQL_INVERSE  SYSTEM TABLE     NULL
DB               DBA              SYS_TRIGGERS     SYSTEM TABLE     NULL
DB               DBA              SYS_VIEWS        SYSTEM TABLE     NULL

209 Rows. -- 1890 msec.
SQL>

  4. You can stop the Virtuoso Database Server by running — 

    virtuoso-stop.sh dbpedia

  5. You can restart the Virtuoso Database Server by running — 

    virtuoso-start.sh dbpedia

Performance Notes

Please be aware of the following, which impact the performance and utility of your AMI:

Troubleshooting

If you encounter any problems resolving the sample DBpedia URIs listed in the steps above, please:

  1. Determine whether Virtuoso is running, with this command 

    ps -ef | grep "virt*" | grep -v grep

  2. Check the log of Virtuoso's most recent activity with one of these commands
    • for the DBpedia instance 

      tail /dbpedia/*.log

    • for the basic instance 

      tail /opt/virtuoso/dbpedia/*.log

      The output of those commands will show you whether the initial Virtuoso DBpedia DB setup (which can take a while due to DB size) is still in progress, the setup encountered some error, or the setup has completed but Virtuoso awaits one of the following commands:

Related Items

CategoryHowTo CategoryODS CategoryVirtuoso CategoryDocumentation CategoryEC2